Regulation 9 Category B—tank washing in Special Areas
Where a Category B substance is unloaded at a port in a Special Area, every tank from which such substance has been unloaded shall be pre-washed and the resulting tank washings shall be discharged into a reception facility at the port of unloading unless—
(a)
unloading was carried out as required by regulation 7 or to the satisfaction of a Marpol surveyor, and
(b)
the substance is not a high residue substance, and
(c)
the residues are to be retained on board for discharge outside a Special Area.